Police say the threat of using a taser flown from Auckland to assist officers during an incident was enough to end a three-hour standoff on the banks of Waikato River.
A 36-year-old man, accused of injuring a police officer, was standing on the edge of the the river in the suburb of Pukete and refusing to surrender.
Police were called by a jogger on Monday morning complaining about a man following her in a car.
When an officer went to talk to the driver and remove his keys, he was dragged about 20 metres before the car hit a tree.
The driver then ran to the nearby river and hid in reeds and a swampy area.
Police say the man's behaviour was irrational and threatening at times and the taser was the best tactical option open to them.
The device and an operator were flown to Hamilton by a police helicopter.
Police negotiators spent time talking with him but officers moved in just before 11.30am confronting him with the taser while police dogs looked on.
The man surrendered and the taser was not used on him.
Inspector Karen Hendrikson says the stun guns have not yet been allocated to Waikato but will be in the near future.
The injured officer is in a stable condition in Waikato Hospital on Monday night.
Police are interviewing the driver. No decision has yet been made on what charges will be laid.